Desktop support for Flutter

Desktop support allows you to compile Flutter source code to a native Windows, macOS, or Linux desktop app. Flutter’s desktop support also extends to plugins—you can install existing plugins that support the macOS or Linux platforms, or you can create your own.

Requirements

To create a Flutter app with desktop support, you need the following software:

Additional Windows requirements

For Windows desktop development, you need the following in addition to the Flutter SDK:

  • Visual Studio 2019 (not to be confused with Visual Studio Code) with the “Desktop development with C++” workload installed, including all of its default components

Additional macOS requirements

For macOS desktop development, you need the following in addition to the Flutter SDK:

Additional Linux requirements

For Linux desktop development, you need the following in addition to the Flutter SDK:

The easiest way to install the Flutter SDK along with these dependencies is by using snapd. For more information, see Installing snapd.

Once you have snapd, you can install Flutter using the Snap Store, or at the command line:

 sudo snap install flutter --classic

If snapd is unavailable on the Linux distro you’re using, you might use the following command:

 sudo apt-get install clang cmake ninja-build pkg-config libgtk-3-dev libblkid-dev liblzma-dev

Create a new project

You can use the following steps to create a new project with desktop support.

Set up

At the command line, perform the following commands to make sure that you have the latest desktop support and that it’s enabled. If you see “flutter: command not found”, then make sure that you have installed the Flutter SDK and that it’s in your path.

 flutter channel dev

 flutter upgrade

 flutter config --enable-<platform>-desktop

Where <platform> is windows, macos, or linux:

 flutter config --enable-windows-desktop

 flutter config --enable-macos-desktop

 flutter config --enable-linux-desktop

To ensure that desktop is installed, list the devices available. You should see something like the following (you’ll see Windows, macOS, or Linux, depending on which platforms you’ve enabled):

 flutter devices
1 connected device:

Windows (desktop) • windows • windows-x64 • Microsoft Windows [Version 10.0.18362.1082]
macOS (desktop) • macos • darwin-x64 • Mac OS X 10.15.5 19F101
Linux (desktop) • linux • linux-x64 • Linux

You might also run flutter doctor to see if there are any unresolved issues. It should look something like the following on Windows:

[✓] Flutter (Channel master, 1.22.0-10.0.pre.196, on Microsoft Windows [Version 10.0.18362.1082], locale en-US)
[✓] Visual Studio - develop for Windows (Visual Studio Professional 2019 16.6.2)
[✓] VS Code (version 1.48.2)
[✓] Connected device (1 available)

On macOS, you might see something like the following:

[✓] Flutter (Channel master, 1.18.0-10.0.pre, on Mac OS X 10.15.4 19E287, locale
    en-US)
[✓] Xcode - develop for iOS and macOS (Xcode 11.2)
[✓] Chrome - develop for the web
[✓] VS Code (version 1.44.2)
[✓] Connected device (3 available)

On Linux, you might see something like the following:

 flutter doctor
[✓] Flutter (Channel master, 1.20.0-1.0.pre.132, on Linux, locale en_US.UTF-8)
[✓] Linux toolchain - develop for Linux desktop
[✓] VS Code (version 1.33.1)
[✓] Connected device (1 available)

If flutter doctor finds problems for a platform you don’t support, you can ignore those warnings. You don’t have to install Android Studio and the Android SDK, for example, if you’re writing a Linux desktop app.

After enabling desktop support, restart your IDE. You should now see windows (desktop), macOS (desktop), or linux (desktop) in the device pulldown.

Create and run

Creating a new project with desktop support is no different than creating a new Flutter project for other platforms.

Once you’ve configured your environment for desktop support, you can create and run a desktop app either in the IDE or from the command line.

IDE

After you’ve configured your environment to support desktop, make sure you restart the IDE if it was already running.

Create a new app in your IDE and it automatically creates iOS, Android, and desktop versions of your app. (And web, too, if you’ve enabled web support.) From the device pulldown, select windows (desktop), macOS (desktop), or linux (desktop) and run your app to see it launch on the desktop.

Command line

To create a new app that includes desktop support (in addition to mobile support), run the following commands, substituting myapp with the name of your project:

 flutter create myapp

 cd myapp

To launch your app from the command line, enter one of the following commands from the top of the package:

 flutter run -d windows

 flutter run -d macos

 flutter run -d linux

Build a release app

To generate a release build run one of the following commands:

 flutter build windows

 flutter build macos

 flutter build linux

Distribution

In general, we don’t recommend releasing a desktop app until desktop support is stable. There are not yet full instructions, or tooling support, for making distributable applications. However, here is some information about how to use the current build output on other machines for testing purposes.

Windows

The executable can be found in your project under build\windows\runner\<build mode>\. In addition to that executable, you need the following:

  • From the same directory:
    • all the .dll files
    • the data directory
  • The Visual C++ redistributables. You can use any of the methods shown in the deployment example walkthroughs on the Microsoft site. If you use the application-local option, you need to copy:
    • msvcp140.dll
    • vcruntime140.dll
    • vcruntime140_1.dll

Place the DLL files in a directory next to the executable and the other DLLs, and bundle them together in a zip file.

macOS

The .app is self-contained, and can be distributed as-is.

Linux

For information on publishing a Linux app to the Snap Store, see Build and release a Linux desktop app.

As the tooling solidifies, stay tuned for updates on other ways to distribute a Linux desktop app.

Add desktop support to an existing Flutter app

To add desktop support to an existing Flutter project, run the following command in a terminal from the root project directory:

 flutter create .

This adds the necessary desktop files and directories to your existing Flutter project.

macOS-specific support

The following information applies only to macOS development.

Entitlements and the App Sandbox

macOS builds are configured by default to be signed, and sandboxed with App Sandbox. This means that if you want to confer specific capabilities or services on your macOS app, such as the following:

  • Accessing the internet
  • Capturing movies and images from the built-in camera
  • Accessing files

Then you must set up specific entitlements in Xcode. The following section tells you how to do this.

Setting up entitlements

Managing sandbox settings is done in the macos/Runner/*.entitlements files. When editing these files, you shouldn’t remove the original Runner-DebugProfile.entitlements exceptions (that support incoming network connections and JIT), as they’re necessary for the debug and profile modes to function correctly.

If you’re used to managing entitlement files through the Xcode capabilities UI, be aware that the capabilities editor updates only one of the two files or, in some cases, it creates a whole new entitlements file and switches the project to use it for all configurations. Either scenario causes issues. We recommend that you edit the files directly. Unless you have a very specific reason, you should always make identical changes to both files.

If you keep the App Sandbox enabled (which is required if you plan to distribute your app in the App Store), you need to manage entitlements for your application when you add certain plugins or other native functionality. For instance, using the file_chooser plugin requires adding either the com.apple.security.files.user-selected.read-only or com.apple.security.files.user-selected.read-write entitlement. Another common entitlement is com.apple.security.network.client, which you must add if you make any network requests.

Without the com.apple.security.network.client entitlement, for example, network requests will fail with a message such as:

flutter: SocketException: Connection failed
(OS Error: Operation not permitted, errno = 1),
address = example.com, port = 443

For more information on these topics, see App Sandbox and Entitlements on the Apple Developer site.

Hardened runtime

If you choose to distribute your application outside of the App Store, you need to notarize your application for compatibility with macOS 10.15+. This requires enabling the Hardened Runtime option. Once you have enabled it, you need a valid signing certificate in order to build.

By default, the entitlements file allows JIT for debug builds but, as with App Sandbox, you may need to manage other entitlements. If you have both App Sandbox and Hardened Runtime enabled, you may need to add multiple entitlements for the same resource. For instance, microphone access would require both com.apple.security.device.audio-input (for Hardened Runtime) and com.apple.security.device.microphone (for App Sandbox).

For more information on this topic, see Hardened Runtime on the Apple Developer site.

Plugin support

Flutter on the desktop supports using and creating plugins.

Using a plugin

To use a plugin that supports desktop, follow the steps for plugins in using packages. Flutter automatically adds the necessary native code to your project, as with iOS or Android.

We recommend the following plugins, which have been updated to work for desktop apps:

Use the following links to find all packages on pub.dev that support desktop apps. These links lists all packages, not just plugin packages. (Remember that plugin packages, or plugins, provide an interface to platform-specific services.)

Writing a plugin

When you start building your own plugins, you’ll want to keep federation in mind. Federation is the ability to define several different packages, each targeted at a different set of platforms, brought together into a single plugin for ease of use by developers. For example, the Windows implementation of the url_launcher is really url_launcher_windows, but a Flutter developer can simply add the url_launcher package to their pubspec.yaml as a dependency and the build process pulls in the correct implementation based on the target platform. Federation is handy because different teams with different expertise can build plugin implementations for different platforms. You can add a new platform implementation to any endorsed federated plugin on pub.dev, so long as you coordinate this effort with the original plugin author.

For more information, including information about endorsed plugins, see the following resources:

Samples and codelabs

Write a Flutter desktop application
A codelab that walks you through building a desktop app that integrates the GitHub GraphQL API with your Flutter app.

You can run the following samples as desktop apps, as well as download and inspect the source code to learn more about Flutter desktop support.

Flutter Gallery running web app, repo
A samples project hosted on GitHub to help developers evaluate and use Flutter. The Gallery consists of a collection of Material design widgets, behaviors, and vignettes implemented with Flutter. You can clone the project and run Gallery as a desktop app by following the instructions provided in the README.
Photo Search app
A sample app built as a desktop application that uses the following desktop-supported plugins:

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31/12/2020 by flutter 0

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